Aminomethyl Propanediol

Aminomethyl propanediol is primarily a pH adjuster/buffering agent used at low concentrations (typically well under 1%) to neutralize acids and stabilize formulations. Patch-test and clinical experience suggest low inherent irritation at these use levels, but because it is alkaline and directly influences final product pH, stinging can occur in compromised barriers or when paired with acids. Overall it is generally well-tolerated, yet not completely inert, so I score it as gentle rather than very gentle. Safety Notes: Aminomethyl propanediol is primarily used as a pH adjuster/buffer, so in many leave-on lotions/serums and rinse-off cleansers it appears at low, utility levels around ~0.05–0.5% (often used alongside carbomer/acrylates systems and neutralizing acids). Higher-strength consumer products such as strong AHA/BHA peel solutions, exfoliating toners, and other low-pH actives can push neutralizer demand upward, with observed OTC formulations reaching roughly 1–5% to achieve target pH and viscosity. There is no specific EU/FDA maximum for this ingredient in cosmetics, so the upper end is driven by formulation/pH needs and sensory limits rather than a formal regulatory cap.